U.S. patent application number 11/341189 was filed with the patent office on 2007-08-16 for methods and devices for a minimally invasive placement of a rod within a patient.
This patent application is currently assigned to SDGI Holdings, Inc.. Invention is credited to Jeff R. Justis.
Application Number | 20070191836 11/341189 |
Document ID | / |
Family ID | 37944413 |
Filed Date | 2007-08-16 |
United States Patent
Application |
20070191836 |
Kind Code |
A1 |
Justis; Jeff R. |
August 16, 2007 |
Methods and devices for a minimally invasive placement of a rod
within a patient
Abstract
The present application is directed to devices and methods for
positioning a rod within a patient. One embodiment of the device
may include an elongated inserter having a first end and a second
end. A connector may be attached to the second end of the inserter
for releasably connecting to the rod. The connector may be
adjustable between a first position with the rod substantially
coaxially aligned with the inserter, and a second position with the
rod substantially perpendicular to the inserter.
Inventors: |
Justis; Jeff R.;
(Germantown, TN) |
Correspondence
Address: |
COATS & BENNETT, PLLC
1400 Crescent Green, Suite 300
Cary
NC
27518
US
|
Assignee: |
SDGI Holdings, Inc.
|
Family ID: |
37944413 |
Appl. No.: |
11/341189 |
Filed: |
January 27, 2006 |
Current U.S.
Class: |
606/279 ;
606/103 |
Current CPC
Class: |
A61B 17/7085 20130101;
A61B 17/7001 20130101; A61B 17/7004 20130101; A61B 17/7002
20130101 |
Class at
Publication: |
606/061 ;
606/103 |
International
Class: |
A61F 2/30 20060101
A61F002/30; A61B 17/58 20060101 A61B017/58 |
Claims
1. A device to insert a rod into a patient comprising: an elongated
inserter having a first end and a second end; and a connector
attached to the second end of the inserter and having a connection
to releasably connect to the rod; the connector being adjustable
between a first position with the rod coaxially aligned with the
inserter, and a second position with the rod substantially
perpendicular to the inserter.
2. The device of claim 1, wherein the connector comprises an arm
that is pivotally connected to the second end and extends outward
beyond the inserter.
3. The device of claim 1, further comprising a sleeve comprising a
hollow interior sized to receive the inserter, the sleeve being
axially movably along the inserter.
4. The device of claim 3, wherein the sleeve is connected to the
rod at a point laterally spaced apart from a connection point
between the connector and the rod.
5. The device of claim 1, wherein the inserter further comprises a
sleeve that extends around the inserter and is pivotally attached
to the rod.
6. A device to insert a rod into a patient comprising: an elongated
member attached to the rod at a first connection; and a sleeve
having a hollow interior and sized to extend around the member, the
sleeve being movably positioned on the member and connected to the
rod at a second connection, the second connection being spaced from
the first connection; axial movement of the sleeve along the member
causes the rod to move relative to the member between a first
orientation with the rod and member being coaxially aligned and a
second orientation with the rod being outwardly angled relative to
the inserter.
7. The device of claim 6, wherein the member is substantially
perpendicular to the rod in the second orientation.
8. The device of claim 6, wherein the member and the sleeve are
releasably mounted to the rod.
9. The device of claim 6, wherein the sleeve completely surrounds
the member.
10. A device to insert a rod into a patient comprising: a guide
comprising a sidewall forming an interior region and comprising a
slot through the sidewall at a distal end; an elongated inserter
comprising a first end and a second end, the inserter sized to fit
through the interior region; a connector attached to the second end
of the inserter and comprising a connection to releasably connect
to the rod; the connector adjustable between a first position with
the rod coaxially aligned with the inserter and having an overall
width less than the interior region, and a second position with the
rod substantially perpendicular to the inserter and extending
through the slot in the sidewall.
11. The device of claim 10, further comprising a sleeve positioned
around the inserter and being releasably connected to the rod, the
sleeve axially movable along the inserter between a first location
causing the rod to be coaxially aligned with the inserter and a
second location with the rod substantially perpendicular to the
inserter.
12. The device of claim 10, further comprising a door connected to
the distal end of the guide, the door being movable between a first
orientation with an upper edge of the door being in proximity to
the guide, and a second orientation with the upper edge being
spaced away from the guide.
13. The device of claim 12, wherein the door has a U-shape to mate
with the guide in the first orientation.
14. The device of claim 10, further comprising a door connected to
a distal end of the guide and being oriented at an angle that
extends outward from the distal end.
15. A method of positioning a rod within an anchor in a patient,
the method comprising the steps of: attaching a rod to a distal end
of an inserter and coaxially aligning the rod with the inserter;
moving the rod and the inserter into the patient with the rod and
inserter coaxially aligned; after moving the rod and inserter a
distance into the patient, pivoting a first end of the rod outward
from the inserter; positioning the rod into the anchor while the
rod is pivoted outward from the inserter; and detaching the rod
from the inserter while positioned in the anchor and removing the
inserter from the patient.
16. The method of claim 15, wherein the step of moving the rod and
the inserter into the patient comprises moving the rod and inserter
through an interior section of a guide that is inserted within the
patient.
17. The method of claim 16, further comprising pivoting the rod
outward from the inserter and through a slot in the guide.
18. The method of claim 15, further comprising pivoting the rod
outward from the inserter an amount to be substantially
perpendicular to the inserter and positioning the rod into the
anchor.
19. The method of claim 15, further comprising detaching the rod
from the inserter when the rod is substantially perpendicular to
the inserter.
20. The method of claim 15, wherein the step of moving the rod and
the inserter into the patient is performed percutaneously.
21. The method of claim 15, further comprising simultaneously
moving the rod into the patient and pivoting the rod outward from
the inserter.
22. The method of claim 15, wherein the step of moving the rod and
inserter into the patient comprises moving the rod and inserter
along a door and into a guide.
23. A method of positioning a rod within an anchor in a patient,
the method comprising the steps of: attaching a rod to a distal end
of an inserter and coaxially aligning the rod with the inserter;
moving the rod and the inserter through an interior of a guide and
into the patient a first distance with the rod and inserter
coaxially aligned; after moving the rod and inserter the first
distance into the patient, pivoting a first end of the rod outward
from the inserter with a first end of the rod moving through a slot
in the guide; positioning the rod into a first anchor that is
aligned with the guide and the first end of the rod into a second
anchor that is spaced away from the first anchor; and removing the
inserter from the rod and maintaining the rod in the first and
second anchors.
24. The method of claim 23, further comprising moving the rod and
inserter through the interior of the guide beyond first distance
and simultaneously pivoting the first end of the rod outward from
the inserter.
25. The method of claim 23, further comprising pivoting the rod
outward from the inserter about 90.degree. and positioning the rod
into the first and second anchors.
Description
BACKGROUND
[0001] The present application is directed to methods and devices
for implanting a rod within a patient and, more specifically, to
methods and devices for implanting a rod in a minimally invasive
manner.
[0002] The spine is divided into four regions comprising the
cervical, thoracic, lumbar, and sacrococcygeal regions. The
cervical region includes the top seven vertebral members identified
as C1-C7. The thoracic region includes the next twelve vertebral
members identified as T1-T12. The lumbar region includes five
vertebral members L1-L5. The sacrococcygeal region includes nine
fused vertebral members that form the sacrum and the coccyx. The
vertebral members of the spine are aligned in a curved
configuration that includes a cervical curve, thoracic curve, and
lumbosacral curve.
[0003] Vertebral rods may be implanted to support and position the
vertebral members in one or more of these regions. The rods extend
along a section of the spine and may include a curved configuration
to conform to the curvature of the spine. Attachment mechanisms are
used to attach the rods to the vertebral members. The attachment
mechanisms attach to a vertebral member, and also attach to the
rod.
[0004] Insertion of the rod into a patient normally requires a
large incision through the skin and detachment of the paravertebral
muscles to access the vertebral members. This type of procedure
usually results in a longer surgical procedure with greater amounts
of blood loss and increased anesthesia time. These procedures may
also have a higher risk of infection, require a longer
postoperative recovery time, and result in addition pain and
discomfort to the patient.
SUMMARY
[0005] The present application is directed to devices and methods
for positioning a vertebral rod within a patient. One embodiment of
the device may include an elongated inserter having a first end and
a second end. A connector may be attached to the second end of the
inserter for releasably connecting to the rod. The connector may be
adjustable between a first position with the rod substantially
coaxially aligned with the inserter, and a second position with the
rod substantially perpendicular to the inserter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a perspective view of a rod extending between
anchors according to one embodiment.
[0007] FIG. 2 is a side view of an inserter connected to a rod and
positioned in a first orientation according to one embodiment.
[0008] FIG. 3 is a side view of an inserter connected to a rod and
positioned in a second orientation according to one embodiment.
[0009] FIGS. 4A-E are side views of inserting a rod to an anchor
according to one embodiment.
[0010] FIGS. 5A-D are side views of inserting a rod to an anchor
according to one embodiment.
[0011] FIG. 6 is a perspective view of a rod extending between
anchors according to one embodiment.
DETAILED DESCRIPTION
[0012] The present application is directed to devices and methods
for inserting a rod within a patient. In one embodiment, a rod is
initially connected to an inserter with a pivoting connection. The
connection provides for the rod move from a first position that is
aligned with the inserter to a second position that is laterally
angled relative to the inserter. The inserter and rod are initially
in the aligned first position while being inserted through a guide
and into a patient. The rod is then laterally angled outward
towards the second position. The second position may provide for
positioning the rod within anchors.
[0013] FIG. 1 illustrates one embodiment for using the devices and
methods. Anchors 100 are secured within the patient with a channel
102 being positioned to receive a rod 20. In one embodiment, the
anchors 100 are secured to one or more vertebral members. Guides 40
may be attached to the anchors 100 and provide a conduit for
inserting the rod 20 to the anchors 100. The rod 20 and inserter 30
are inserted into the guide 40a. The inserter 30 is manipulated to
move the rod 20 through the guide 40a. As the rod 20 approaches a
distal end of the guide 40a, the rod 20 pivots outward from the
inserter 30 and moves through a slot 41 in the guide 40a. The rod
20 is further pivoted outward with a first end of the rod 20
positioned in the first anchor 100 and the second end in a second
anchor 100. After the rod 20 is positioned within the anchors 100,
the inserter 30 may be detached from the rod 20 and removed from
the guide 40.
[0014] FIG. 2 illustrates one embodiment with a rod 20 connected to
an inserter 30. Rod 20 has an elongated body 23 that extends
between a first end 21 and a second end 22. Rod 20 may have a
variety of cross-sectional shapes and sizes, and may have a variety
of lengths. In one embodiment, rod 20 has a circular
cross-sectional shape. In one embodiment as illustrated in FIG. 2,
one or both of the first and second ends 21, 22 may be tapered
towards a reduced end. In another embodiment as illustrated in
FIGS. 5A-5D, rod 20 has a substantially continuous width
throughout.
[0015] In one embodiment, inserter 30 has an elongated shape with a
width sized to fit within the guide 40. In one embodiment as
illustrated in FIG. 2, inserter 30 comprises an elongated member 31
and an exterior sleeve 37. Member 31 has an elongated shape that
extends between a proximal end 32 and a distal end 33. In one
embodiment as illustrated in FIG. 2, the distal end 33 tapers
towards a point. Member 31 may have a variety of shapes and sizes
depending upon the context of use. In one embodiment, member 31 is
substantially straight. In another embodiment, member 31 may be
curved.
[0016] In one embodiment, an arm 34 is connected to the distal end
33 of the elongated member 31. The arm 34 is sized to extend
outward from the member 31 and connect to the rod 20. In one
embodiment, arm 34 includes two opposing sections each positioned
on a side of the member 31. A first connector 35 may pivotally
connect the arm 34 to the distal end 33 of the member 31. In one
embodiment, first connector 35 is a pin that extends through the
distal end 33. A second connector 36 connects to the rod 20. In one
embodiment, the arm 34 comprises opposing sections each having a
ball fitting that mates with an indent in the rod 20 to form the
second connector 36. The first and second connectors 35, 36 allow
the arm 34 to be pivotally connected to the member 31 and the rod
20.
[0017] A sleeve 37 may be positioned over the member 31 and sized
to axially move along the member 31. In one embodiment, sleeve 37
includes a cylindrical shape having open distal and proximal ends.
In one embodiment, sleeve 37 extends partially around the member
31. An extension 38 may extend outward from the distal end to
connect with the rod 20. In one embodiment, extension 38 includes
opposing members positioned to contact opposite outer sides of the
rod 20. In one embodiment, extension 38 extends over the arm 34
when the rod 20 and inserter 30 are coaxially aligned as
illustrated in FIG. 2. A connector 39 at the end of the extension
38 connects with the rod 20. In one embodiment, connector 39
includes a ball fitting that extends outward from each of the
opposing members and seats within detents in the rod 20.
[0018] Rod 20 is pivotally connected with the inserter 30. In one
embodiment, rod 20 is relatively movable between a first
orientation as illustrated in FIG. 2 with rod 20 coaxially aligned
with the inserter 30, and a second orientation as illustrated in
FIG. 3 with the rod 20 that is substantially perpendicular to the
inserter 30. In one embodiment, sleeve 37 and extension 38 are
axially moved in a proximal direction relative to the member 31
causing the rod 20 to pivot. As best illustrated in FIGS. 2 and 3,
the axial movement of the sleeve 37 and extension 38 applies a
lifting force to the rod 20 at the connector 39. Connector 39 moves
in a proximal direction relative to connector 36. The amount of
relative movement between the sleeve 37 and member 31 controls the
angle of the rod 20 relative to the inserter 30.
[0019] The inserter 30 may be detachable from the rod 20.
Detachment of the inserter 30 from the rod 20 may occur in a
variety of different manners. In one embodiment, connectors 39 and
36 comprise ball and detent joints. Detents are positioned on the
rod 20 at the connection locations. Corresponding ball fittings
extend outward from each of the extension 38 and arm 34. The ball
and detent connections are sufficient to maintain attachment
between the rod 20 and inserter 30 through movement within the
guide 40 and moving from the first orientation to the second
orientation. A force applied to the inserter 30 in a proximal
direction along the guide 40 breaks the connection at each of the
connectors 39, 36 and allows removal of the inserter 30.
[0020] Another embodiment features the rod 20 having slots that
extend into the rod from one of the lateral sides. A first pin
extends between two opposing sections that comprise the arm 34, and
a second pin extends between two opposing sections that comprise
the extension 38. The first pin is positioned within the first slot
to form the first connector 36, and the second pin is positioned
within the second slot to form the second connector 39. When the
rod 20 is coaxially aligned with the inserter 30 as illustrated in
FIG. 2, the pins remain within the slots and allow the inserter 30
to position and manipulate the rod 20. When the rod 20 reaches a
predetermined angle relative to the inserter 30, the pins slide out
from the slots and the rod 20 is detached from the inserter 30. In
one embodiment, the rod 20 detaches when it is substantially
perpendicular to the inserter 30.
[0021] Guide 40 provides a conduit for inserting the rod 20 and
accessing the anchors 100. In one embodiment, guide 40 has an outer
wall with a hollow interior that is sized to receive the rod 20 and
inserter 30. Guide 40 has a length adequate for percutaneous access
to the anchor 100 with the distal end positioned at the anchor 100
and the proximal end positioned exterior to the patient. In one
embodiment, the distal end of the guide 40 attaches to the anchor
100. In one embodiment, the guide 40 is inserted into a first
incision made to the patient. The distal end of the guide 40 is
positioned at the member to which the anchor 100 is to be attached.
In one embodiment, the guide 40 is inserted with the distal end
adjacent to a vertebral member. The anchor 100 is inserted through
the guide 40 and attached to the vertebral member. In one
embodiment, once the anchor 100 is attached to the vertebral
member, the guide 40 is attached to the anchor 100. In another
embodiment, the guide 40 remains detached from the anchor 100.
[0022] Anchors 100 may have a variety of constructions. In one
embodiment, anchors 100 are multi-axial screws having a movable
head with a channel 102 for receiving the rod 20. Various other
anchors 100 may be employed with the present application.
[0023] FIGS. 4A-4E illustrates one embodiment of inserting the rod
20 into the patient. As illustrated in FIG. 4A, the rod 20 is
initially attached to the inserter 30. Rod 20 and inserter 30 are
moved through the guide 40a in the direction indicated by arrow A
towards the anchors 100. In one embodiment, the rod 20 and inserter
30 are coaxially aligned creating a minimum profile for insertion
in the guide 40a. In another embodiment, the rod 20 may be out of
alignment but still provide a reduced profile to fit within the
guide 40a. In one embodiment, the physician grasps a distal end of
the inserter 30 and manually inserts the rod 20 and inserter 30
into the guide 40a.
[0024] As the rod 20 and inserter 30 continue to move into the
guide 40a in the direction of arrow A, the rod 20 is positioned in
proximity to a slot 41 at the distal end of the guide 40a. Rod 20
is then pivoted outward in the direction of arrow C as illustrated
in FIG. 4B. In one embodiment, this pivoting motion may be caused
by axially moving the sleeve 37 in a proximal direction as
indicated by arrow B. FIG. 4C illustrates rod 20 pivoted further
outward in the direction of arrow C. This continued movement is
caused by the proximal movement of sleeve 37 in the direction of
arrow B to the member 31. In another embodiment, the outward motion
is caused by moving the sleeve 37 in a distal direction.
[0025] In one embodiment, rod 20 and inserter 30 continue to move
downward into the guide 40a while rod 20 is pivoted outward. In one
embodiment, the pivoting motion of the rod 20 may begin when the
first end 21 of the rod 20 is aligned with a top edge of the slot
41. In another embodiment, outward motion begins when the second
end 22 of the rod 20 is aligned with a top edge of the slot 41. In
another embodiment, the pivoting motion begins when the first end
21 nears the anchor 100.
[0026] As illustrated in FIGS. 4C and 4D, the pivoting motion
causes the first end 21 of the rod 20 to approach the second anchor
100 associated with guide 40b. Guide 40b may also include a slot 41
to allow the first end 21 to move over the anchor 100. Slots 41 may
extend through a single section of the sidewall of the guides 40a,
40b, or may extend through two or more sections of the sidewall. In
one embodiment as illustrated in FIG. 4D, rod 20 passes through
both guides 40a, 40b. In one embodiment, the tapered shape of the
first end 21 eases the movement through the body as the rod 20
pivots outward from the guide 40a.
[0027] As illustrated in the embodiment of FIG. 4D, rod 20 may be
pivoted outward to a position that is substantially perpendicular
to the inserter 30. The inserter 30 continues to move down the
guide 40a causing the rod 20 to seat within the anchors 100.
Specifically, a portion of the rod 20 adjacent to the first end 21
seats within the channel 102 of the first anchor 100, and a portion
of the rod 20 adjacent to the second end 22 seats within the
channel 102 of the second anchor 100. The placement of the rod 20
within the anchors 100 may vary depending upon the context. In one
embodiment, both anchors are positioned towards a middle portion of
the rod 20. In one embodiment, both anchors are positioned in
proximity to one of the ends 21, 22. In other embodiments, the rod
20 seats within more than two anchors 100.
[0028] After the rod 20 is seated to the anchors 100, inserter 30
is removed from the rod 20 as illustrated in FIG. 4E. In one
embodiment, an upward force applied to the inserter 30 in the
direction of arrow A causes the connectors 36, 39 to release from
the rod 20. This allows the rod 20 to remain within the anchors
100, and for the inserter 30 to be removed from the guide 40a.
Guides 40a, 40b may also be used for attaching the rod 20 within
the anchors 100. In one embodiment, guides 40a, 40b provide
conduits for inserting fasteners 201. In one embodiment, an
insertion tool 200 having an elongated body 202 moves fasteners 201
through the guides 40a, 40b and connects the rod 20 to the anchors
100.
[0029] FIGS. 5A-5D illustrate another embodiment. Inserter 30
includes a member 31 having an arm 34 that attaches to the rod 20
at connector 36. In this embodiment, inserter 30 does not include
an outer sleeve. Guide 40 has a larger width and includes a ramped
section 42 at the distal end. The ramped section 42 may be
positioned at a variety of angles. In one embodiment, the ramped
section 42 has a continuous slope. In another embodiment, ramped
section 42 includes a variable slope. In one embodiment as
illustrated in FIG. 5A, ramped section 42 terminates at the anchor
100. In another embodiment, ramped section 42 terminates at a point
laterally offset from the anchor 100. As illustrated in FIG. 5A,
inserter 30 with the rod 20 attached are moved downward into the
guide in the direction of arrow A. In this initial orientation, the
rod 20 and inserter 30 are coaxially aligned. In another
embodiment, the rod 20 is angled outward relative to the inserter
30 but still sized to fit within the guide 40.
[0030] As the inserter 30 and rod 20 travel down the guide 40, the
first end 21 of the rod 20 contacts the ramped section 42 causing
the rod 20 to pivot outward as illustrated in FIG. 5B. Continued
movement of the inserter 30 in the direction of arrow A causes the
first end 21 to slide along the ramped section 42. As the distal
end of the inserter 30 nears the start of the ramped section 42,
the outward angle of the rod 20 increases.
[0031] As the rod 20 and inserter 30 continue to move, the first
end 21 slides along the ramped section 42. In one embodiment as
illustrated in FIG. 5C, the first end 21 may further slide across
the anchor 100. As illustrated in FIG. 5D, continued movement may
result in the inserter distal end 33 sliding along the ramped
section 42. At this position, rod 20 may be substantially
perpendicular to the inserter 30. Inserter 30 is moved downward
into the guide 40 until the rod 20 seats within the anchor 100. The
inserter 30 may then be detached from the rod 20 and removed from
the guide 40.
[0032] FIG. 6 illustrates another embodiment having a door 48. Door
48 has an elongated body that extends between first and second
ends. In one embodiment as illustrated in FIG. 6, door 48 has a
curved cross-sectional shape forming a substantially U-shape that
is sized to guide the inserter 30 and rod 20. In another
embodiment, door 48 forms an enclosed section through which the
inserter 30 and rod 20 are inserted. The door 48 is positioned
adjacent to the slot 41 in the guide 40a to allow the inserter 30
and rod 20 to be moved to the anchor 100.
[0033] In one embodiment, door 48 is attached after the guide 40a
is positioned in the patient. Door 48 is inserted into the patient
through a separate incision from the guide 40a. The first end of
the door 48 is positioned adjacent to the distal end of the guide
40a. In one embodiment, door 48 includes a connection 47 that
connects the door 48 to the guide 40a.
[0034] In another embodiment, door 48 is mounted to the guide 40a
prior to insertion into the patient. The door 48 and the guide 40a
are inserted together into the patient. In one embodiment, door 48
is movably mounted to the guide 40a. A connection 47 attaches the
first end of the door to the distal end of the guide 40a. The door
48 may attach directly at the distal end of the guide 40a, or may
be spaced upward on the guide 40a but within proximity to the
distal end. The connection 47 provides for the door 48 to pivotally
move between a first, extended position as illustrated in FIG. 6,
and a second, closed position with the door 48 in proximity to the
guide 40a. In one embodiment, the U-shaped door 48 cradles around
the guide 40a when the door 48 is in the second, closed
position.
[0035] In one embodiment, the guide 40a and attached door 48 are
inserted into the patient when the door 48 is in the closed
position. After insertion, the door 48 is moved to the first,
extended position. After the rod 20 is positioned in the anchors
100 and the inserter 30 is detached and removed from the patient,
the door 48 is returned to the closed position. The door 48 and
guide 40a are then removed from the patient when the door 48 is
closed. In one embodiment, door 48 is non-movable and remains in
the open position.
[0036] The door 48 is aligned at an angle relative to the anchors
100 to reduce the amount of outward movement necessary for the rod
20 to move relative to the inserter 30. In the previous embodiments
described for FIGS. 4 and 5, the rod 20 moves to be substantially
perpendicular to the inserter 30. With the door 48, the amount of
movement is reduced. In one embodiment, the door 48 is at an angle
of about 45.degree. relative to the anchor 100. Therefore, the rod
20 moves about 45.degree. during insertion to extend across the
anchors 100.
[0037] The term "distal" is generally defined as in the direction
of the patient, or away from a user of a device. Conversely,
"proximal" generally means away from the patient, or toward the
user. Spatially relative terms such as "under ", "below ", "lower
", "over ", "upper ", and the like, are used for ease of
description to explain the positioning of one element relative to a
second element. These terms are intended to encompass different
orientations of the device in addition to different orientations
than those depicted in the figures. Further, terms such as "first
", "second ", and the like, are also used to describe various
elements, regions, sections, etc and are also not intended to be
limiting. Like terms refer to like elements throughout the
description.
[0038] As used herein, the terms "having ", "containing ",
"including ", "comprising" and the like are open ended terms that
indicate the presence of stated elements or features, but do not
preclude additional elements or features. The articles "a ", "an"
and "the" are intended to include the plural as well as the
singular, unless the context clearly indicates otherwise.
[0039] The present invention may be carried out in other specific
ways than those herein set forth without departing from the scope
and essential characteristics of the invention. The present
embodiments are, therefore, to be considered in all respects as
illustrative and not restrictive, and all changes coming within the
meaning and equivalency range of the appended claims are intended
to be embraced therein.
* * * * *